Stewardess call indicator and buzzer operating switch



Aug. l5, 1961 T. WJJENTGES 2,996,702

sTEwARDEss CALL INDICATOR AND BUzzER OPERATING swITcx-x Filed March l,1960 2 Sheets-Sheet 1 I N VEN TOR.

rra//vfy fafmf/ Aug. 15, 1961 T. w. JENTGl-:s 2,996,702

sTEwARDEss CALL INDICATOR AND BUZZER OPERATING SWITCH 2 SheetswSheet 2Filed March l, 1960 fa A/ #l 45 4% JNVENToR. Tivo/w15 WMS/vrees BY 2 s g2,996,702 STEWARDESS CALL DIDICATOR AND BUZZER OPERATING SWITCH ThomasW. Jentges, Orange, Calif., assignor to Marco Industries Company,Anaheim, Calif., a corporation of California Filed Mar. 1, 1960, Ser.No. 12,653 11 Claims. (Cl. S40- 311) This invention relates toilluminated push button switches in general and has as its object toprovide an illuminated push button switch particularly adapted for useas a stewardess call button.

object of the invention is to provide a plunger and barrel type switchembodying a multipleposition plunger which, when depressed to the fullextent of its travel, will actuate a signal (eg. an audible annunciator)to alert the stewardess to the call being made; which, when released,will be spring-retracted to an intermediate position in which theannunciator is deenergized and will become self latching in saidintermediate position and will eieet the energizing of an indicatorlight in the stewardess compart-ment and simultaneously illuminate apush button lens on the outer end of the plunger to indicate thepassenger seat of origin of the call.

A -furt-her object is to provide such a switch which can be manuallyactuated by the stewardess when she answers the passengers call, torestore the plunger to a retracted position in -which all circuits aredeenergized.

The invention contemplates an improved call button of a plunger typehaving a plunger actuating stem adapted to be pressed for projecting theplunger inwardly and to be manually grasped to withdraw the plungeryfrom an intermediate latching position to a retracted position, saidstem being of hollow tubular `form and further functioning as a lens capcovering a small, low power indicator light by which the stem willbeilluminated to indicate the closed condition of the switch.

A particular object of the invention is to provide a sturdy, durablecombination of parts providing for the closing of three separatecircuits in response to inward projection of the switch plunger,yieldingly accom-modating the bottoming of the plunger to itsfull-travel position in which an annunciator is energized, automaticallysetting itself at the intermediate position for energizing a pair ofindicator lights, when pressure on the plunger is released, and yieldingto positive outward pull upon the plunger stem lfor resetting it to itsretracted position in which all contacts are disengaged.

Other objects and advantages will become` apparent in` the ensuingspecification and appended drawing in which:

FIG. 1 is an axial sectional view of a stewardess call button embodyingmy invention;

FIG. 2 is a side view thereof partially in axial section, viewing theinternal parts in a direction at right angles to that of FIG. l,approximately along the line 2 2 of FIG. 1, some of the internal partsbeing broken away to better illustrate the construction;

FIG. 3 is a forward end View of the device;

FIG. 4 is a cross sectional view thereof taken on the line 4 4 of FIG.l;

FIG. 5 is a cross sectional View thereof taken on the line 5--5 of FIG.l;

FIG. 6 is a cross sectional view thereof taken on the line 6-6 of FIG.l;

FIG. 7 is a cross sectional View of the device taken on the line 7-7 ofFIG. l;

FIG. 8 is a schematic diagram illustrating the use of the device in astewardess call circuit;

FIG. 9 is an end view of the plunger slide and its attached lamp socket;

FIG. l0 is a fragmentary sectional detail of the latching means.

GENERAL DESCRIPTION `OF THE INVENTION Referring now to the drawings indetail, I have shown therem, as an example of one form in which theinventron may be embodied, a stewardess call button switch embodying, ingeneral, a barrel and fixed contact assembly A, a mounting collarassembly B, and a plunger and movable contact assembly C. The assembly Ccomprlses, in general, a metallic tubular slide 1t) which is mounted fornon-rotatable sliding movement in the mounting collar assembly B, acontact head 11 secured to the forward end of slide 10 and carrying aseries of electrical contacts, a socket 12 4for a small low powerlelectric lamp bulb 13, and a combined push button stem and lens 14 whichis attached to the socket 12 and cooperates therewith in enclosing thelamp 13. Stem 14 is of translucent material so as to be illuminated bythe seatindicator lamp |13 when the latter is energized, thus indicatingthat the call button has been actuated at the passengers seat.

The barrel assembly A includes four fixed contacts in the form ofterminal bars 15, 16, 117 and 13 (see FIGS. 6, l and 2). The terminalbars 15, 16, 17 and 18 are secured and connected to terminal screws 1,2, 3 and ll respectively.

Mounted upon the terminal bar 18 is a resilient con-- tact brush 19which is in sliding contact with an integral contact finger 20projecting axially from the inner endv of the slide body 10. Contacts|15, 16 and 17 are adapted to be engaged by respective spring lingers21, 22 and 23- of contact head l1 as the plunger is projected inwardly.Fingers 21, 22, 23 are electrically connected to one another.

Relationship t0 controlled crcut.-Referring now to FIG. 8, the terminal4 is adapted to be connected by a suitable conductor, as indicated, toone side of a current source 25, lfrom which current is brought throughthe contacts 19, 20, to the slide 10. From the slide 10, connection ismade directly through socket 12 to one side of the indicator light 13.From the center contact of' indicator light 13, connection is madethrough a sliding contact pin 24 to the contact lingers 21, 22, 23,connected thereto in parallel. Forward projection of plunger Ci to anintermediate position will engage iinger 21 against contact 115.Terminal '.1 is adapted to be connected to the other side of currentsource 25 by a suitable con-- ductor as indicated, and thus theengagement of contact 15 by finger 21 establishes the circuit to theindicator light 13 Simultaneously, contact finger 22 will engage contact16. Terminal 2 of contact 16 is adapted to be connected by a suitableconductor to an indicator light 26 in the stewardess compartment, theindicator light 26 being; connected by a conductor 27 to the currentsource 25. Conductor 27 -is arranged to connect indicator light 2'6 inseries with current source 25 and the connections through terminal 1,contacts 15, 21, contacts 22, 16, and terminal 2, whereby in theintermediate position of plunger projection, a circuit will beestablished to the indicator light 26 through these connections.

Terminal 3 is adapted to be connected by a suitable conductor 28 to anaudible annunciator device 29 such as a buzzer or bell, in series withcurrent source 215, terminal 1, contacts 15, 21, and contacts 23, 17,whereby upon `further projection of the plunger C to a bottomingposition, this circuit will be closed at contacts 17, 23 to actuate theannunciator 29, while the circuits through 3 f Y indicator lights 13 and26 remain closed due to the sliding connections between contact fingers21, 22 and their respective contact bars 15 and 16.

DETAILED DESCRIPTION Barrel unit A.-Barrel unit A comprises an insulatorbarrel 30 having a substantially closed, solid integral forward end 38and a counterbore 31 extending therefrom to an open rear end definedwithin a radial outturned fiange 32. Each of the terminal bars 15, 16,17, 18 includes a shank portion 33 having in its inner face, femalethread segments 34 mating with the male threads of the correspondingterminal screws 1, 2, 3, 4. Shanks 33 are joined to the respectivecontact bars 15 etc. by offset shoulders 35 which locate against anannular shoulder 36 defined in the barrel 30 as the bottom ofcounterbore 31, The shanks 33 are fitted against the outer wall of screwsockets 37 which are formed in the solid forward end 38 of the barrel30. Screw sockets 37 are of U-shaped cross section as shown in FIG. 3,and are tapped with female thread segments 39 of approximately 180arcuate extent in the semi-cylindrical inner side of each socket, theouter side of the socket being substantially squared to receive therespective contact shank 33. Thus the terminal screw on one side mesheswith the thread segments 34 of a respective terminal bar shank 33 and onits opposite side meshes with the thread segments 39 of a respectiveterminal socket 37 in the insulating material of the barrel end 38. Theengagement in the socket threads 39 positions the terminal screw againstaxially shifting movement, and the screw in turn, by its meshingengagement with terminal bar threads 34, positions the respectiveterminal bar against axially shifting movement, and snugly clamps theterminal bar shank outwardly against the squared outer wall f therespective socket 37. Conventional lock washers as indicated may beinterposed between the heads of the terminal screws and the end ofbarrel 30 to lock the screws against unthreading movements.

Mounted in the counterbore 31 in the open rear end of barrel 30 is a camsleeve 41 having a frusto-conical internal camming shoulder 42 definedas the rear side of an inwardly thickened rim 43 which terminates in athin cylindrical lip 44. At the opposite end of cam sleeve 41 is aradial flange 45 which seats against barrel fiange 32. Rim 43 and lip 44have a common cylindrical inner wall providing an insulator bearing landfor the contact fingers 21, 22, 23 in their retracted, open positions.The lip 44 also provides radial positioning support for the ends of theterminal bars 15, 16, 17, 18 which are abutted against the end wall ofsleeve 41 defined by rim 43 as indicated. This end abutting engagementprovides for accurate positioning of the contact bars -18 while theterminal screws 1-4 are being threaded into place to secure them intheir sockets.

The contact :brush 19 is secured to the inner face of terminal bar 18 byany secure means such as the tubular rivet 47 extended through andriveted in an aperture end bar 18. As shown in FIG. l, brush 19 extendsthrough the annular space defined radially between the periphery ofslide body finger '20 and the cylindrical inner wall of cam sleeve rim43. Brush 19, in its position bearing against finger 20, is flexedoutwardly from a normal unstressed configuration, and thus bearsresiliently against the finger to maintain good electrical contact asthe plunger is shifted axially to its several positions.

Plunger C is spring loaded toward its retracted position by a conicallyspiral coil spring 48 the apex end of which extends into a centralcavity 49 in the closed end 38 of barrel 3l) and is secured by a rivet50 press-fitted into the end 38. The base end of spring 48 bears againstthe metal collar portion 51 of contact finger 23 which is seated againstthe forward end of plunger C.

Mounting collar assembly B.-Assembly B includes a slide bearing sleeve55 of insulating material having a cylindrical periphery (FIG. 5) andhaving internal walls including diametrically opposed segmentalcylindrical walls 56 and diametrically opposed fiat chordal side walls57. Bearing sleeve 55 has an integral radial flange 58 at its forwardend, seated against flange 45 of cam sleeve 41. Bearing sleeve 55 isencased in a mounting collar 59, preferably of metal, having at itsforward end a flat annular shoulder fiange 60 seated against bearingsleeve flange 58, an integral cylindrical n'rn 61 binding theperipheries of flanges 32, 45 and 58, and terminating in a securing lip62 which is turned inwardly and clamped against flange 32 to secure themounting collar unit B to the barrel unit A. An integral lug 63 onbearing sleeve flange 58 projects axially forwardly through a notch infiange 45 and is engaged in a notch in fiange 32 to locate vthe bearingsleeve 55 and the cam sleeve 41 in proper rotational positioning withrespect to barrel 30.

vMounting collar 59 is adapted to be secured in an aperture in a panel(e.g. interior side wall trim panel of an airplane) by means of anassembly of washer and locknuts 64 threaded onto a male thread 65 on thecollar 59.

DETAILED DESCRIPTION- PLUNGER UNIT C Slide 10 of plunger unit C includesa cylindrical tubular intermediate wall 76 and, on its respective ends,arcuate lands 71, 72 arranged in diametrically opposed pairs and fittedto the arcuate inner walls 56 of bearing sleeve 55. Lands 71 and 72 haveparallel flat side faces 73 (FIG. 9) which are fitted to the flatinternal side walls 57 of bearing sleeve 55 to hold the slide 10 againstrotation within bearing sleeve 55 while accommodating free axial slidingmovement therein. The lands 71, 72 may be initially formed as circularanges and reduced by machining off the opposite sides thereof to providethe fiat side faces 73 which are approximately tangent to the peripheryof tubular intermediate body 70.

In its forward end, slide 10 has a central opening defined by a shallowinternal radial flange 75, which is filled by an insulator washer 76.Flange 75 provides a shoulder against which is seated an insulatorwasher 77 Within the cylindrical bore of slide 10. A larger insulatorwasher 78 is seated against the forward end face of slide 10. Sandwichedbetween washer 78 and the rear end of contact head 11 is a thin fiatcollar 79 from which the spring contact fingers 21 and 22 project asintegral extensions, 90 apart (FIG. 7). Extending through the assemblyof Washers 77, 76, 78, the central tubular body 80 of contact head 11,and the collar portion 51 of contact finger 23, is a relatively long,thin walled metal grommet 81 the ends of which are headed over againstthe washer 77 and the collar 51 respectively to secure these parts inassembly. The contact pin 24 is mounted within grommet 81 for free axialsliding movement therein. At its forward end, contact pin 24 has anoutwardly fianged head 82 functioning as a stop for engagement againstthe forward end of grommet 81. At its rear end, contact pin 24 has ahead 83 with a recessed end face for engagement with the end contact 84of indicator light bulb 13. A light coil spring 85 encircles therearwardly projecting portion of contact pin 24 and is engaged undercompression between the rear end of grommet 81 and the head 83 toyieldingly position the contact pin in spring loaded engagement withcontact 84.

Contact head 11 includes the tubular central portion 80, encirclinggrommet 81, and a plurality of quartersegmental wings 86 which arecircumferentially spaced to define a series of axially extending slots87, 88, 89 and 90 in which are positioned the respective spring contactfinger 21, 22 and 23 and the straight rigid extension nger 20. At thispoint it may be noted that the contact fingers 21 and 22 projectforwardly from the rear end of contact head 11 whereas the contactfinger 23 projects rearwardly from the forward end of head 11. Thesecontact fingers, of thin spring sheet metal, are formed at asse-'76atheir free ends with inwardly spreading V-shaped contact tips 91 (on thefingers 21 and 22) and 92 (on the finger 23). By reason of theirV-shape, the contact tips 91 will ride over the edges of the cam sleeverim 43 and its lip 44 to move from retracted positions within the camsleeve 41 to contact positions in engagement with the respectiveterminal bars 15, 16, 17 respectively, and will be cammed inwardly whenthe plunger is retracted. Contact head 11 is of insulating material.Collar 79 of contact fingers 21, 22 is vconnected to grommet 81 bysoldering or brazing, and is thus electrically connected to contactfinger 23. The lingers l21, 22, 23 are flexed inwardly from normalunstressed positions by their engagement within the barrel assembly A,and thus are constantly spring-urged outwardly into yielding engagementwith the respective surfaces of these parts. By securing the finger 23to the forward end of contact head 11 and arranging it to extendrearwardly, whereas the lingers 21 and 22 project forwardly, the contacttip 92 of finger 23 is positioned rearwardly of the contact tips `91 offingers 21 and 22. Accordingly, the contact tips 91 will engage theirrespective terminal bars prior to engagement of contact tip 92 againstits terminal bar in the forward projection o'f plunger C.

Indicator light bulb 13 has a metal base ferrule 93 which is receivedwithin a thin walled skirt portion 94 of the socket 12, and therebyelectrically connected to slide 10, and has a thin base flange 95 whichis yieldingly seated against the inner end of skirt `94 by the pressureof contact pin 24. Skirt 94 has an external thread by which it isthreaded into a female thread 96 `in the rear end of the bore of slide10.

Socket 12 includes a relatively thick collar portion 97 projecting fromthe rear end of slide i and provided with an external thread onto whichis threaded the for ward end of the lens-stem 14.

Stem 1'4 includes a thin walled cylindrical body 98- of translucentmaterial such as plastic resin, and has a closed rear end in the form ofan outwardly flanged head 99 with a concave rear end face to receive theiinger tip of the passenger pressing the plunger to actuate the switch.

In one of the segmental wings 86 (FIGS. 7 and 10) is a radial bore 100in lwhich is retained a latch ball 101 urged radially outwardly by acoil spring 102 under compression between the fball 101 .and the bottomof the bore 100. Ball 101 is adapted to drop over the forward edge ofcam sleeve lip 44 through a notch 103` (which provides a cam surface ofinclination opposite to that of shoulder 42) and onto barrel 30, whichsupports ball 1101 against complete outward escape from bore 100, in aposition wherein the ball will provide a latching connection between thecontact head 11 and the forward end of cam sleeve 41 to latch theplunger C in lthe intermediate position thereof.

OPERATION In the operation of my improved call button, the plunger Cwill normally b e retracted as shown in FIG. l, with all three of thecontact fingers 211, 22, 23 withdrawn into the cam sleeve `41 andthereby insulated from contact with the terminal bars 15, 16, 17. Whenthe stewardess is to be called, the pasesnger presses against the head99 at the rear end of plunger C, projecting the plunger forwardly andextending first the contact fingers 21 and 22, andsubsequently the.contact finger 23, out of the cam sleevey 4 1 and int-o contact withtheir respectiveterminal bars 15, i16 and 17. Upon engagement of contactIfingers 21 and 22 with the terminal bars 15 and 16, the two indicatorlamps 13 and 26 will be illuminated as previously described. Continuedforward projection will establish contact of nger 23 against its contactibar 17 shortly prior to bottoming of the contact head 11 against theclosed end 38 of the barrel 30. At this point the return spring 48 willbe highlyv compressed. After holding the plunger in bottomed conditionlong enough to extending peripheral slots, and said plunger having at"actuate the annunciator in the stewardess compartment, the passenger mayremove the pressure on the plunger C, whereupon the spring 48 willreturn it to an intermediate position in which the tip l92 of finger 23has been withdrawn into the cam sleeve 41 but the fingers 21 and 22remain in contact with their terminal bars 15 and 16, thus retaining theilluminated condition of indicator lights 13 and 26.

In this position, latch ball `101 will engage ahead of the end of camsleeve y41 as shown in FIG. l0, and will be effective to latch theplunger C in its intermediate position wherein the circuits to indicatorlights 13- and 26 remain energized while the circuit to annunciator 29is broken. With the two lights 13 and 26 thus energized, the stewardesswill be reminded in the stewardess compartment that the call has not yetbeen answered, and upon proceeding down the aisle, will be able tolocate the seat of the passenger making the call, by the illumination ofthe seat-indicator lamp 13 of the push button that was actuated by thepassenger. After servicing the call, the stewardess may grasp the stem98 by its head 99 and forcibly retract the plunger C to extinguish thelights 1'3 and 26.

In lieu of being in the form of an elongated stem, the lens cap 14 maybe relatively short. In either event, it may be appropriately referredto as a combined lens cap and actuator button, and is so designated inthe ap pended claims.

The sleeve 41, referred to in the appended claims, in most instances, asan insulator sleeve, functions primarily to define an insulator chamberin the rear end of barrel 30, into which the spring contact fingers 22are withdrawn in the retracted position of the plunger. In addition, itscamming shoulder 42 cooperates with the contact tip 92 of spring linger23 to latch the plunger in retracted position as shown in FIG. 2.

I claim:

l. In a stewardesscall button: an insulator barrel; a plurality ofcontact bars mounted in circumferentially spaced relation in the forwardend of said barrel and projecting rearwardly therein in closely spacedparallel relation to the inner 'wall thereof, said contact bars havingrespective terminals for connection to respective stewardess annunciatorand call-indicator light circuits; a plunger mounted in said barrel fornon-rotatable axially sliding movement therein, said plunger includingat its rear end an actuator button; a plurality of spring contactfingers attached to the forward end of said plunger and having free endsproviding respective axially spaced forward and rear contact tipsadapted for successive engagement with respective contact bars as theplunger is projected forwardly from a retracted position throughanintermediate position to a forward limit position, said forwardcontact tip being arranged to engage the contact bar for saidcall-indicator light circuit to energize the same in said intermediateposition and said rear contact tip being arranged to engage the contactbar for said annunciator circuit to energize the same at said forwardlimit position; said barrel having a portion providing an insulatorchamber rearwardly of said contact bars, in which said spring contactfingers are received and insulated from said contact bars in saidretracted pos`ition of said plunger.

2. In a stewardess-call button: an insulator barrel; a-v plurality ofcontact bars mounted in circumferentially spaced relation in the forwardend of said barrel and. projecting rearwardly therein in closely spacedparallel. relation to the inner wall thereof, said contact bars havingrespective terminals for connection to conductors for controllingrespective stewardess annunciator and callindicator light circuits; aplunger mounted in said barrel for non-rotatable axially slidingmovement therein, said plunger includingat its forward end an insulatorhead having aplurality of circumferentially spaced axially its rear endan actuator button; a plurality of spring contact fingers attached tosaid insulator head, retained in said slots, and having free endsproviding respective axially spaced forward and rear contact tipsadapted'for successive engagement with respective contact bars as theplunger is projected forwardly from a retracted position through anintermediate position to a forward limit position, said `forward contacttip being arranged to engage the contact bar for said call-indicatorlight circuit to energize the same in said intermediate position andsaid rear contact tip being arranged to engage the contact bar for saidannunciator circuit to energize the same at said forward limit position;and an insulator sleeve in said barrel rearwardly of said contact bars,in which said insulator head and spring contact lingers are received andinsulated from said contact bars in the retracted position of saidplunger.

3. A call button as defined in claim 2, wherein said insulator head hasa bore extending radially inwardly from its periphery, and including alatch ball caged in said bore and a spring in said bore loading saidball for outward projecting movement from a retracted position in whichit is retained by engagement with the inner wall of said insulatorsleeve, to a position overhanging a forward edge of said insulatorsleeve to latch the plunger in said intermediate position; and a springengaged under compression between the forward end of said plunger andoperative to return the same from said forward limit position to saidintermediate position upon release of pressure on said actuator button.

4. In a stewardess-call button: an insulator barrel having means formounting the same in a support panel; a plurality of contact barsmounted in circumferentially spaced relation in the other end of saidbarrel, projecting rear- Wardly therein in closely spaced parallelrelation to the inner wall thereof, said having respective terminals forconnection to conductors for controlling respective stewardessannunciator and call-indicator light circuits; a resilient contact brushmounted on another of said contact bars and projecting toward said oneend of the barrel in generally parallel spaced relation to the wallthereof; a slide-bearing sleeve of insulating material carried by saidone end of the barrel and having a wall segment of noncircular crosssection; a plunger unit slidably mounted in said bearing sleeve andhaving a part mating with said wall segment to provide for non-rotatableaxial sliding movement of the plunger in said sleeve, said plungercomprising a metallic tubular slide having an integral iinger projectingaxially from its periphery and in sliding engagement with said yieldingcontact brush to connect said slide to said energy source, and aninsulator head attached to the inner end of said slide body section andhaving in its periphery a plurality of axially extending slots; aplurality of spring contact lingers attached to said insulator head,retained in said slots, and having free ends providing respectiveaxially spaced forward and rear contact tips adapted for successiveengagement with respective contact bars as the plunger is projectedforwardly :from a retracted position through an intermediate position toa forward limit position, said forward contact tip being arranged toengage the contact bar for said call-indicator light circuit to energizethe same in said intermediate position and said rear contact tip beingarranged to engage the contact bar for said annunciator circuit toenergize the same at said forward limit position; and an insulatorsleeve in said barrel rearwardly of said contact bars, in which saidinsulator head and spring contact lingers are received and insulatedfrom said contact bars in the retracted position of said plunger.

5. ln a stewardess-call button: an insulator barrel; a plurality ofterminals in the forward end of said barrel including a pair ofterminals for connection to one side of a current source and to one sideof a stewardess annunciator and including a third terminal forconnection to the other side of said current source and the other sideof said annunciator; a pair of contact bars and 'a resilient contactbrush mounted in said forward end of the barrel in circumferentiallyspaced'relation and projecting rearwardly therein in adjacent spacedparallel relation to the internal wall thereof, said contact bars beingconnected respectively to said pair of terminals and said brush beingconnected to said third terminal; a plunger including a metallic slidemounted in said barrel for non-rotatable axially sliding movementtherein, said plunger including, at its rear end, an indicator light anda combined lens cap and actuator button covering said indicator lightand projecting from the rear end of the barrel for actuation of theplunger; a rigid contact linger connected to and projecting forwardlyfrom the forward end of said slide and in sliding contact with saidbrush to establish a connection to one side of said indicator light; aconductor element arranged for connection to the other side of saidindicator light and projecting forwardly through the forward end of saidslide; and a pair of spring contact lingers connected to said conductorelement at the forward end of said slide and having free ends providingaxially spaced forward and rear contact tips positioned for engagementrespectively with said contact bars upon forward projection of saidplunger from a retracted position through an intermediate position andto a forward limit position, said forward contact tip being arranged toengage the contact bar that is connected to the terminal for connectionto the said one side of the current source, whereby to complete acircuit to said indicator light in the intermediate position of theplunger, and said rear contact tip being arranged for engagement withthe contact bar that is connected to the terminal for connection to saidannunciator, whereby to actuate the latter in the forwardly projectedposition of said plunger, said barrel having a portion providing aninsulator chamber rearwardly of said contact bars, in which said springcontact ngers are received and insulated from said contact bars in saidretracted position of said plunger.

6. In a stewardess-call button: an insulator barrel; first, second,third and fourth terminals mounted in the forward end thereof, said rst,second and third terminals being adapted for connection to one side of acurrent source, to a stewardess compartment indicator light and to anannunciator respectively and said fourth terminal being adapted forconnection to the other sides of said current source, said stewardesscompartment light and said annunciator respectively; rst, second andthird contact bars and a resilient contact brush mounted in said forwardend, connected respectively to said first, second, third and fourthterminals and projecting rearwardly in adjacent spaced parallel relationto the inward wall of said barrel; a plunger including a tubularmetallic slide mounted in said barrel for non-rotatable axially slidingmovement therein, a socket in the rear end of said plunger for mountinga seat-indicator light having a central end contact and a base ferruleconstituting a lateral contact to be electrically connected to saidslide body through said socket; and a combined lens cap and actuatorbutton attached to said socket for covering said seat indicator lightand actuating said plunger; a contact rod mounted in the forward end ofsaid slide and adapted to engage said indicator light central contact atits rear end; and three spring contact lingers attached to the forwardend of said plunger and electrically connected to one another and tosaid contact rod, said spring contact lingers having free ends providinga pair of forward contact tips and a rear contact tip disposedrearwardly of said forward contact tips, said forward contact tips beingarranged for engagement with the contact bars of the said first andsecond terminals upon projection of the plunger forwardly from aretracted position to an intermediate position, whereby to complete thecircuit to said seat-indicator light and to said stewardess compartmentindicator light respectively at said intermediate position, and saidrear contact tip being arranged for engagement with the contact bar ofsaid third terminal while said pair of contact tips remain in contactwith their respective contact bars, upon projection of said plunger to aforward limit position, whereby to actuate said annunciator at saidforward limit position; said barrel having a portion providing aninsulator chamber rearwardly of said contact bars, in which said springcontact fingers are received and insulated from said contact bars insaid retracted position of said plunger.

7. In a stewardess-call button: an insulator barrel; a plurality ofcontact bars mounted in circumferentially spaced relation in the forwardend of said barrel and projecting rearwardly therein in closely spacedparallel relation to the inner wall thereof, said contact bars havingrespective terminals for connection to respective stewardess annunciatorand call-indicator light circuits; a cam sleeve of insulating materialextending rearwardly in said barrel from the rear end of said contactbars and having forwardly and inwardly inclined cam shoulder means atits forward end; a plunger mounted in said barrel for non-rotatableaxially sliding movement therein, said plunger including at its rear endan actuator button; a plurality of spring contact lingers attached tothe forward end of said plunger and having free ends providingrespective axially spaced forward and rear contact tips adapted forsuccessive engagement with respective contact bars as the plunger isprojected forwardly from a retracted position through an intermediateposition to a forward limit position, said forward contact tip beingarranged to engage the contact bar for said call-indicator light circuitto energize the same in said intermediate position and said rear contacttip being arranged to engage the contact bar for said annunciatorcircuit to energize the same at said forward limit position; said springcontact fingers being withdrawn into said cam sleeve in said retractedposition of the plunger, and said rear contact tip, in said retractedposition, being shifted radially outwardly into latching contact withsaid cam shoulder means to yieldingly retain the plunger in saidretracted position, and upon forward projection of the plunger, beingcammed inwardly by camming engagement with said shoulder means.

8. A call button as defined in claim 7, including cooperating means onthe forward end of said plunger and in said barrel for yieldinglylatching the plunger in said intermediate position, and including springmeans engaged under compression between the forward end of said plungerand the forward end of said barrel for returning the plunger from saidforward limit position to said intermediate position.

9. In a stewardess call button: an insulator barrel having at its rearend means for mounting the same in a support panel; a plurality ofcontact bars mounted in circumferentially spaced relation in the forwardend oct said barrel and having respective terminals for connectionrespectively to a stewardess annunciator, to a call-indicator lightcircuit, and to one side of an electrical energy source; a resilientcontact brush mounted on another of said contact bars and projectingtoward said one end of the barrel in generally parallel spaced relationto the wall thereof; a slide-bearing sleeve carried by said rear end ofthe barrel and having a wall segment of non-circular cross section; yanda plunger slidably mounted in said bearing sleeve and having a partmating with said wall segment to provide for non-rotatable axial slidingmovement of the plunger in said sleeve, said plunger comprising ametallic tubular slide having an integral finger projecting axially fromone side thereof and in sliding engagement with said yielding contactbrush to connect said slide to the other side of said energy source, aninsulator head attached to the inner end of said slide and having in itsperiphery a plurality of axially extending slots; spring contact lingersmounted to respective ends of said insulatorhead and extending axiallyin said slots, one projecting forwardly and the other rearwardly, andhaving free ends spaced from one another axially; and a sleeve ofinsulating material surrounding said contact head and normally receivingsaid contact lingers, said iingers being projected from said sleeve intosuccessive contact with said contact bars upon forward projection ofsaid plunger, whereby to first energize said call-indicator lightcircuit and then said annunciator, in successive stages of forwardprojection of said plunger.

10. In a stewardess call button: an insulator barrel having at its rearend means for mounting the same in a support panel; a plurality of fixedcontacts mounted in circumferentially spaced relation in the forward endof said barrel and having respective terminals for connectionrespectively to a stewardess annunciator, to a call-indicator signal,and to an electrical energy source; a resilient contact brush mounted insaid forward end of the barrel and projecting rearwardly in generallyparallel spaced relation to the internal wall thereof; and a plungeruni-t non-rotatably and slidably mounted in said rear end of the barrel,said plunger unit including a metallic tubular slide having an integralfinger projecting axially from one side thereof at its periphery and insliding engagement with said contact brush to connect said s-lide tosaid energy source, anda tubular insulator head attached to the innerend of said slide; a lamp socket on the rear end of said slide formounting a lamp having a lateral contact ferrule and a central endcontact; a metallic grommet extending axially through said insulatorhead; a contact rod extending through said grommet and engaging said endcontact; and a plurality of spring contact fingers connected to saidgrommet and projecting axially and having axially spaced contact tipsfor successive engagement with said terminals in an arrangement such asto energize first said call-indicator signal and indicator light andthen said annunciator, in successive stages of forward projection ofsaid plunger.

1l. A call button as defined in claim 10, including an insulator washerinterposed between said insulator head and the inner end of said slide,wherein forwardly projecting spring contact finger has a flat collarportion disposed between said insulator washer and said insulator head,and wherein said rearwardly extending spring contact finger has a collarportion secured to the forward end of said grommet.

References Cited in the tile of this patent UNITED STATES PATENTS1,751,972 Bobroi ...t- Mar. 25, 1930 1,826,501 Bobroif Oct. 6, 19312,614,194 Lester Oct. 14, 1952 2,814,698 Miller Nov. 26, 1957

